Mechanism for the operation of railroad track switches

ABSTRACT

The invention relates to a railroad switch operating mechanism wherein there are a reversible electric motor, a volumetric pump coupled thereto a double acting hydraulic jack the action of which is transmitted to the operating rod of the switch by means of a bell crank axially secured in a sealed block containing oil which serves as lubricant and a fluid for the operation of the jack. The combined pump-jack-block forming a closed hydraulic circuit.

United States Patent [191 Crutsch et al.

[ Oct. 15, 1974 MECHANISM FOR THE OPERATION OF RAILROAD TRACK SWITCHES [76] Inventors: Louis Crutsch, 12, Chemin du Tour des Bois, Le Vesinet, Yvelines; Bernard Ducassou 73 rue Gambetta, Suresnes l-lauts de Seine, both of France [22] Filed: Nov. 24, 1972 [21] Appl. No.: 309,612

[30] Foreign Application Priority Data Nov. 25, 1971 France 71.42215 [52] US. Cl. 246/258 [51] Int. Cl B611 17/00, E01b 7/00 [58] Field of Search 245/393, 415, 430, 257,

[56] References Cited UNITED STATES PATENTS 1/1931 Coleman 246/258 2,769,900 11/1956 Maile 246/258 3,136,509 6/1964 Magnus 246/258 3,158,345 11/1964 Wilhelm et al. .1 246/258 Primary Examiner-M. Henson Wood, Jr. Assistant Examiner-Richard A. Beitsch [5 7 ABSTRACT The invention relates to a railroad switch operating mechanism wherein there are a reversible electric motor, a volumetric pump coupled thereto a double acting hydraulic jack the action of which is transmitted to the operating rod of the switch by means of a bell crank axially secured in a sealed block containing oil which serves as lubricant and a fluid for the operation of the jack. The combined pump-jack-block forming a closed hydraulic circuit.

8 Claims, 5 Drawing Figures PATENTED our 1 51974 SHEEI 10F 5 PATENTEU I 51374 3.842.256

SHEET 5 OF 5 MECHANISM FOR THE OPERATION OF RAILROAD TRACK SWITCHES The presently used self-locking and electrically controlled mechanisms for operation railroad switches make use of the same functionning principle which consists in affecting a direct conversion of the torque from a reversible electric motor, by means of a dry gear train, into a linear face to draw a lever which travels in a member formed integrally of the usual operating bar or stem of the switch, ensuring the non-reversibility of the mechanism. Toward the end of the travel movement a frictionally operating torque limiting device, disposed either at the beginning or at the end of the kinematic sequence, functions to absorb the excess energy supplied by the motor as well as the inertia of the whole.

Aside from their in efficiency such mechanisms also exhibit some further drawbacks, such as:

They necessitate the use of many electrical contacts of operation and control, each of which is subjected to wear.

They make use of a frictional connector which is rather fragile and has little durability, particularly if it is located at the head end of the kinematic system where high rates of revolution prevail at the end of each cycle of operation, or is somewhat and unresponsive and unrealiable if its located at the other end of the kinematic system where high torque at low r.p.m. prevail.

It is by mechanical friction that is absorbed the ex cess energy developed by the electric motor, the duration of the energized period of which is made to lasts much longer that which is required for the completion of an actual operation of the mechanism. However the friction elements which are used for this purpose fare poorly under the excessive work load imposed on them; consequently they do not last long.

The present invention relates to a mechanism for the operation of railroad switches that exhibits more of the aforementioned drawbacks of existing mechanisms. The mechanism of the invention is particularly advantageous owing to the fact that, as it does not comprise parts which are subjected to intense wear, the rubbing contacts having been replaced by rolling contacts throughout, it can remain in service for practically unlimited periods of time. Furthermore, the mechanism of the invention is bathed in oil, thereby elliminating the needs for periodic maintenanace checks which in practice are often detrimental to the preservation of the mechanisms optimum characteristics and good working order.

Another advantage of the mechanism of the invention is that it can readily be installed as a replacement for other mechanisms without requiring the making of significant modifications.

Essentially, the novel mechanism of the invention is a combination of a reversible electric motor. a volumetric pump directly coupled thereto and, a doubleacting hydraulic jack actuating the switch stern by means of a bell crank axially secured to a sealed housing that also serves as a reservoir for the oil used as lubricant for the mechanism and as hydraulic fluid for the operation of the hydraulic jack", through a closed pump-jack-reservoir system.

The end of one of the levers composing the bell crank is formed as a fork having two branches and the end of each branch presents an oblique vertical face, each face is adapted to be parallel to the horizontal axis of the jacks piston rod at one of the extreme positions of the bell crank. These faces cooperate with a roller carried by the said piston rod to render the mechanism non-reversible is it reaches one or the other of its extreme positions.

According to the invention there is also provided, a self-locking device which acts jointly with -a stabilizing device of the piston rod to avoid all risks of creeping motion of the rod, such as, for instance, under the influence of vibrations from the passing of railroad convoys.

The stabilizing device includes two small forks which are mounted on a vertical axis for pivoted movements against the housing'action of a spring and, are engaged by a roller disposed at the end of the piston rod of the jack as the stroke end positions thereof are reached.

Each of the small forks advantageously presents a cam that operates a terminal contact.

Relatively to the hydraulic system itself, a valve is provided as means for compensating for the difference in capacity between the two chambers, which is attributable to the presence of the piston rod in one of them.

A practical embodiment of the switch operating mechanism of the invention is schematically shown in the drawing annexed hereto, wherein:

FIG. 1 is a plan view; FIG. 2 is a sectional view taken on line 11-11 of FIG.

FIG. 3 is a fractional side view;

FIG. 4'is a schematic flow diagram approximately corresponding to FIG. 1; and;

FIG. 5 is a plan view on a lesser scale of an installation of the mechanism on a track.

A reversible electric motor 1 drives a hydraulic gear pump 3 through the intermediary of a resilient coupling 2. The pump 3 feeds a jack 4 the rod 5 of which is terminated by a cap 6 carrying coaxial rollers 7, 8 and 9, rotating about a common vertical axis. The rollers 8 ac tuate two superimposed fork members 10 integral of a vertical shaft 11 at the lower end of which is secured to a crank 12 adjustable lengthwise, about the end axis 13 of which is pivotally connected the operating stem 14 of the switch and the length of which is also adjustable. The combination of fork members 10, shaft 11 and crank 12 forms one member which may be referred to as a square set or bell crank.

The rollers 7 and 9 are guiding rollers which rotate in contact with parallel guides 15 and 16 fixedly secured inside the housing block 17 closed and sealed by cover 18. The housing block 17 and its cover 18 are studily constructed and rigid. The shaft 11 rotates in conical roller bearing units 21 and 22, respectively secured in block 17 and cover 18 and provided with commonly known sealing and protective means.

The housing block 17 constitutes a reservoir 23 for the oil, the normal level of which therein is indicated by reference numeral 24. The oil is conveniently selected so as to retain its desirable properties throughout the full range of the exterior temperatures of -30 C to C, and contains no additives altering its lubricating properties.

The whole mechanism is fitted inside a housing 25 which is closed and sealed by cover 26 hinged at 27 and presenting locking means 28.

Some handles 29 are provided on housing 25 to permiteasier handling of the mechanism, which is secured over the rail ties by means of angles 31 and intermediate cross pieces 32 (see FIG. There is provided a sealed collar 33 on the electric cable.

According to the invention, the two branches of the forks present end disposed surfaces 34, 35 between which the angle is such that at each extreme position of the rod 5 of the jack there is always one of these surfaces which is parallel to the rod axis to ensure selflocking of the mechanism by bearing on the rollers 8 normally to their axis of rotation in the cap 6.

On the other hand, the cover 18 presents two small forks 50, adapted for pivotal movements around each of axes 52 and presenting a cam 53 which acts on the pusher of an electrical switch 54 controlling the lighting of a control signal at the switching station. The small forks 50 are disposed along the path of the upper roller 9, that actuates them at it reaches the end of it displacement. To avoid overloading of the drawing at FIG. 1, only one of the two small forks 50 was shown.

The hydraulic system is particularly shown at FIG. 4. It mainly comprises a simple suction valve 40, a pressure controlled valve 41 and two preloaded backflow valves 43 and 44 respectively-raised by the pump according to the direction of its rotation, all these elements being connected between themselves the pump, the jack and the reservoir, by means of the appropriate passages,

The operation is as follows; referring to A as being the extreme left position of piston 19 on FIG. 4, and 10 B as the extreme position of same to the right.

To cause movement of the piston of from A to B, the pump 3 pushes fluid through the conduit 45 and draws same through conduit 46. However, the chamber 47 of the jack has greater capacity than the chamber 48, in view of the presence of the rod of the jack 5 in the latter, the supply of the oil required for filling the chamber 47 is achieved through the valve 40 which enables the pump to draw from the reservoir 23 through conduit 49.

After of the stroke of piston 19 has been reached, the pump 3 continues to run for a short predetermined period of time (a few seconds) and the oil pumped from reservoir 23 during the time is returned thereto through the conduit 59, owing to the opening of the preloaded relief valve 44.

To bring about a displacement the piston 19 from B to A, the direction of rotation of the motor 1 and pump 3 is reversed. This time the pump draws fluid through the conduit 45 and forces it through the conduit 46. The volume of the chamber 47 being greater than that of chamber 48 it is necessary to allow dumping toward the reservoir 23 of the excess'oil. This is why according to the invention there has to be provided a control valve 41 which connects, by means of a pressure tap 51, with the conduit 46 and thereby allows the excess oil that comes from chamber 47 to return to reservoir 23, by passing through conduits 42 and then 49. Upon the piston having reached the end of its travel, the pump 3 continues to turn during a few seconds, causing the oil to flow by the return conduit 59 to reservoir 23, through the preloaded relief valve 43.

The conduits 49 and 59 discharge into the reservoir 23, high above the level 24 of the oil therein, in order .to avoid the risk of air entering into the hydraulic system, in whatever position the whole mechanism may be placed while it is being handled and during transportation. In similar way, the nose portion of the jack 4 is submerged in the oil, so that any leak that might develop around the rod thereof would not result in air entering.

As was indicated, at the two opposite extreme positions of the rod 5 of the jack, one or the other of the surfaces 34 or 35 of the forks 10 lies parallel to the axis of the rod and is consequently normal to the axis of the corresponding roller 8. That position is a dead center that makes the mechanism non-reversible, and consequently ensure itself-locking by simple means that cannot come out of adjustment.

In addition to this control function, the small forks 50, which are recalled by an unshown spring, stabilize the jack, their bearing on the roller 9 preventing creep of the rod 5 under the influence of vibrations due to the passing of a train.

It has to be understood that like other such mechanisms, the switch operating mechanism of the invention can also be provided with manual means whereby it may be manually operated in any emergency; such means are not necessarily novel per se; they include level 60 shown in FIG. 1, and pinion gears 62, 63 shown on FIG. 2. This multiplier transmission is used to set the shaft of the motor in rotation by known means.

The linear displacement of the rod 5 of jack 4 in one direction or the other is converted into a 60 rotation of the shaft 11, through the action of forks 10 on rollers 8, The nonreversibility of the mechanism is ensured in the last mm. of displacement at each end of the path followed by the rod 5 the strokes of which is 200 mm. long. 7

At the end of each stroke, the motor 1 continues turning and the pump 3 pushes oil toward the reservoir 23 through one or the other of the preloaded valves 43, 44 after the cam 53 hasappropriately engaged one of the contacts 54 which ensures signalling on the control board of the switching station. 4

In a practical embodiment the operation take 3 seconds for a load of 300 daN. The preloaded valves 43 and 44, are set at bars which allows loads of up 450 daN.

It can be seen that the entire mechanism, which does not have any wearing part, is a very simple one that requires no maintenance.

It will be appreciated that the invention allows simplifled, so called for wires control, according to which the mechanism comprises non shut-off contact at the end each movement, which particularly simplifies the cable laying and connections that must be made when installing same in the field. In fact, after the end of each stroke of the switch needle blades, in'one direction or the other, the motor and the pump keep on turning without ill effect, on account of the closed oil discharge circuit, until the electrical power thereto is cut off, from the switching station by means of a time delay breaker. Nothing should prevent the installation of a device of the invention to replace a device of the prior art normally requiring eight wires circuit by, for instance, utilising only four of these existing wires.

It is to be understood that various other embodiments of the invention can be designed and that various components thereof can be modified without departure from the scope of the invention.

We claim:

1. A railroad switch operating mechanism essentially thereto and a double-acting hydraulic jack adapted to mounted on a sealed housin g contairiirigfil, saidoil serving as lubricant for the mechanism and as fluid for the operation of the hydraulic jack.

2. Hydraulic mechanism as claimed in claim 1, characterized in that the said motor, pump and jack are mounted on said sealed housing, and said sealed housing is rigidly constructed to serve as a base for the mechanism track.

3. Mechanism as claimed in claim 2, wherein are provided a self-locking device and a device for stabilizing the rod of the jack, to eliminate the risks of creeping motion of said switch stem, for instance, as an effect of vibrations from the passing of trains.

4. Mechanism according to claim 3, characterized by the fact that the device for stabilizing the rod consists of two small forks adapted to pivot around a vertical reached.

5. Mechanism according to claim 4, characterized by the fact that each small fork comprises a cam which actuates a signalling switch.

6. Hydraulic mechanism as claimed in claim 5, characterized by the fact that the preloading springs of the valves are adjustable, to permit changing the operating stress applied on the stem of the switch.

7. Mechanism according to claim 1, characterized by the fact that it comprises a system of preloaded valves ensuring the return of the oil to the reservoir after the rod of the the jack had reached one or the other of its stroke end positions.

8'. Hydraulic mechanism according to claim 1, characterized by the fact that a relief valve is provided as means whereby to compensate for the difference be- 1 tween the capacities of the two chambers of the double-acting jack, due to the presence of the said rod thereof in only one of these.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Inventor) Louis CRUTSCH and Bernard DUCASSOU It is certified that error appears in the above-identified patent and that said Letters Patentare hereby corrected as shown below:

Col. 1, line 32, "lasts" should read: last line 33, "that" should read than Col. 2, line 5, "is" should read: as

line 39, "of" should read: with line 41 "to" should be cancelled;

Col. 3, line 30, the second "of" should be cancelled;

line 39, the first "of" should be cancelled;

' Col. 4, line 47, the word: of should be inserted before "each movement".

Signed let? this 8th day of Apri 1. 197.5.

(333$) Attest:

a C. EIQZRiYEL-aLL DAT RUTH C. I'IASODT Commissioner of Patents attesting U'.'f'1cer and Trademarks 

1. A railroad switch operating mechanism essentially characterized by the novel combination of a reversible rotary electric motor, a volumetric pump coupled thereto and a doubleacting hydraulic jack adapted to actuate the switch stem by means of a bell crank axially mounted on a sealed housing containg oil, said oil serving as lubricant for the mechanism and as fluid for the operation of the hydraulic jack.
 2. Hydraulic mechanism as claimed in claim 1, characterized in that the said motor, pump and jack are mounted on said sealed housing, and said sealed housing is rigidly constructed to serve as a base for the mechanism track.
 3. Mechanism as claimed in claim 2, wherein are provided a self-locking device and a device for stabilizing the rod of the jack, to eliminate the risks of creeping motion of said switch stem, for instance, as an effect of vibrations from the passing of trains.
 4. Mechanism according to claim 3, characterized by the fact that the device for stabilizing the rod consists of two small forks adapted to pivot around a vertical axis and against the biassing action of a spring and upon being engaged by a roller carried by the rod of the jack, as positions at opposite ends of the stroke of rod are reached.
 5. Mechanism according to claim 4, characterized by the fact that each small fork comprises a cam which actuates a signalling switch.
 6. Hydraulic mechanism as claimed in claim 5, characterized by the fact that the preloading springs of the valves are adjustable, to permit changing the operating stress applied on the stem of the switch.
 7. Mechanism according to claim 1, characterized by the fact that it comprises a system of preloaded valves ensuring the return of the oil to the reservoir after the rod of the the jack had reached one or the other of its stroke end positions.
 8. Hydraulic mechanism according to claim 1, characterized by the fact that a relief valve is provided as means whereby to compensate for the difference between the capacities of the two chambers of the double-acting jack, due to the presence of the said rod thereof in only one of these. 